Final answer:
The major limitation of ozone and UV disinfection in water treatment is their inability to provide residual protection against potential pathogens after the initial treatment.
Step-by-step explanation:
The major limitation of ozone and UV disinfection is their inability to provide residual protection. Both methods are effective in killing or inactivating various pathogens, including bacteria, protozoa, and viruses. However, they do not leave any residual disinfectant in the water to continue working against potential pathogens after the initial treatment. This means that after the water has been treated, there is no ongoing protection against contamination. As a result, additional disinfectants like chlorine or chloramine may be added to the water after ozonation to provide a residual protective effect throughout a distribution system.
It is also essential to acknowledge that the effectiveness of disinfectants can be affected by several conditions, including temperature, concentration, and the presence of organic matter. Though ozone and UV are potent against a broad range of pathogens, the absence of residual protection is a notable disadvantage, especially in maintaining water safety within distribution pipelines after the initial disinfection process.